Modality-Specific Structure Preserving Hashing for Cross-Modal Retrieval

Hashing-based methods have made great advancements in cross-modal retrieval in both computational efficiency and storage. Learning a common space from different modalities is the common strategy of hashing-based methods, however, relational and structural information between samples in each modality, namely, a modality-specific structure, is always discarded during learning. In addition, cross-modality samples sometimes suffer from inter-class ambiguity and intra-class variability because of the uncertainty of manual labeling. To address these issues, we propose a novel method named Modality-specific structure Preserving Hashing (MsPH), which learns hashes by preserving the local structure and relations between samples in each modality. Moreover, label enhancement is utilized in MsPH to address label ambiguity and variability. Extensive experiments conducted on three benchmark datasets demonstrate the superiority of MsPH under various cross-modal scenarios.